Hello,
That’s not the margin, that’s the padding of the columns https://gyazo.com/16fc9dc02bb5c23e18812999d90a82a5 Edit the columns and set right, left padding to 0 at the design tab if you don’t want to have it. Do you know how to edit the row and column padding, margins using WPBakery settings? Or you need additional screenshots?
Regards